a. Field of Invention
This invention pertains to an apparatus for tilting or turning equipment, and more particularly for pivoting a relatively heavy piece of equipment around a particular axis by a small angle in the range of a few arc degrees, with a great degree of precise resolution and repeatability.
b. Description of the Prior Art
It is frequently desirable to tilt or turn relatively heavy objects around a horizontal, a vertical or an arbitrary axis with an accuracy in the order of an arc second. In certain applications, such as for example in the art of machining precise components, and in the art of directing a beam of light such as laser beam along a preselected axis, it is very important to be able to turn objects with precisely controlled tilt and repeatedly. However all the prior art devices presently available cannot perform these functions with sufficient resolution and repeatability. For example, in Klinger Scientific catalog 584C, published by the Klinger Scientific, 110-20 Jamaica Avenue, Richmond Hill, N.Y. 11418-9970, page 89 an inclination stage type TG is shown which may be used to provide a tilt of about 21/2 degrees. The device disclosed in the catalog consists of two generally parallel plates hingedly connected at one side. The device also includes a micrometer with a nut mounted on the top plate. This nut is engaged by a plunger with a handle. Turning the handle clockwise applies a force on the bottom plate and repulsion forces the top plate upwards. Turning the handle counterclockwise releases the plunger and allows the top plate to sink. The load on the top plate is supported by and transferred directly to the threads of the plunger. The catalog discloses three models for loads of 1.2, 3.8 and 8 kilograms respectively. The weight of the object mounted on the device, its accuracy, and repeatability are limited by the size and pitch of the screw. Furthermore this device is expensive. Another disadvantage of this device is that apparently it is capable of tilting an object mounted on its upper plate only around a substantially horizontal axis.
U.S. Pat. No. 3,807,034 to Pevzner et al discloses a device for trueing a table carrying a heavy object. As shown in FIG. 3 of the Patent, this device makes use of complicated bevel gears 11, 12 and pneumatic cylinder 10, and therefore it is expensive and inaccurate.
U.S. Pat. No. 2,968,517 to Daugherty et al shows a table for tilting and indexing device for tilting heavy objects. The device includes a gimbal 37 positioned at the center of the device and end platforms for pivoting.